A semiconductor manufacturing apparatus is an example of a substrate processing apparatus. A vertical apparatus is known as an example of the semiconductor manufacturing apparatus.
This type of substrate processing apparatus includes a boat as a substrate holding member which accommodates wafers in a reaction tube while holding the wafers in multiple stages. The wafers held by the boat are processed in a process chamber provided inside the reaction tube.
For example, there is known a configuration in which a plurality of wafers to be processed in a batch manner is held by a boat. By simultaneously supplying two or more types of precursor gases to a reaction tube into which the wafers are loaded, a film is formed on each of the wafers.
In addition, there is known a configuration in which a cap heater is installed inside a quartz cylinder and heat energy is supplemented from below a wafer so that a heating time is shortened and a purge gas is prevented from affecting a wafer region.
In a substrate processing apparatus including a reaction tube of a double structure, a gas tends to stay in a gap between an outer tube and an inner tube which constitute the reaction tube. When the gas stays in this gap, byproducts are accumulated in the gap, thus generating particles.